At least 11 wildfires are raging inside the Arctic Circle as the hot, dry summer turns an abnormally wide area of Europe into a tinderbox. The worst affected country, Sweden, has called for emergency assistance from its partners in the European Union to help fight the blazes, which have broken out across a wide range of its territory and prompted the evacuations of four communities. Tens of thousands of people have been warned to remain inside and close windows and vents to avoid smoke inhalation. Rail services have been disrupted. The Copernicus Earth observation programme, which gives daily updates of fires in Europe, shows more than 60 fires burning across Sweden, with sites also ablaze in Norway, Finland and Russia, including in the Arctic Circle. Norway has sent six fire-fighting helicopters in response to its neighbour’s request for assistance.